21366407 has 2 divisors, whose sum is σ = 21366408. Its totient is φ = 21366406.

The previous prime is 21366403. The next prime is 21366463. The reversal of 21366407 is 70466312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21366407 - 2² = 21366403 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21366407.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21366403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10683203 + 10683204.

It is an arithmetic number, because the mean of its divisors is an integer number (10683204).

Almost surely, 2^21366407 is an apocalyptic number.

21366407 is a deficient number, since it is larger than the sum of its proper divisors (1).

21366407 is an equidigital number, since it uses as much as digits as its factorization.

21366407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 29.

The square root of 21366407 is about 4622.3810963615. The cubic root of 21366407 is about 277.4877607350.

The spelling of 21366407 in words is "twenty-one million, three hundred sixty-six thousand, four hundred seven".